I was reminded today of the idea of a chthonian planet. For those of you who may not know (although I'm sure the overwhelming majority already do), a Chthonian planet is a remnant of a gas giant that has been stripped of everything but its core, leaving behind what is more or less a terrestrial planet.
I got to thinking, and wondered whether Mercury might be such an object. I did a quick Google search, but nothing reputable came up. Now I very much doubt that I, being unqualified, could propose an idea that hadn't been seriously proposed and actually turn up being correct. Thing is, I wonder why this question hasn't been posed before. I suspect that there is something quite obvious about the nature of Mercury that means it can not have originated as a chthonian planet that I am not aware of. Please enlighten me.
By the way, mods, I was going to post this in the proving grounds, but then I noticed there was a rule that you mustn't still be developing your idea when you put it there. I've posed this question here, as it seems the only other appropriate place to say this, as I'm not going to be defending my idea, just wondering whether it could be plausible. (Do move it accordingly though, if I was wrong)